White House National Security Advisor Condoleezza Rice testifies this week in public and under oath about the events leading up to the September 11, 2001, terrorist attacks on the United States. She will appear Thursday for more than two hours before the independent commission investigating the attacks.

The commission chairman predicts Condoleezza Rice's testimony will be exciting. Thomas Kean told the NBC television program Meet the Press that the panel hopes to learn a great deal from the president's national security advisor.

"We want to know about what happened and what the differences were between the Bush policies and the policies of the Clinton administration," he said. "We want to know what she heard and what she knew. And of course we want to know what differences there might be between her, Mr. Clarke, and a number of other people we have heard."

Richard Clarke, the former White House counter-terrorism coordinator, recently told the commission that the White House did not pay enough attention to the terrorist threat prior to the September 11th attacks.

His accusations ultimately led President Bush to drop his long-standing opposition to any public testimony by his confidential advisors. After days of White House statements designed to call Mr. Clarke's charges into question, he changed course and announced Condoleezza Rice would appear before the commission under oath and in public session.

Chairman Kean, the top Republican on the commission, told NBC the panel has been surprised by some of the things it has learned in the process of taking testimony from former and current officials. He said the American people are likely to be surprised as well when the commissioners release their final report.

"We will have things in our report on two ends: first the report itself, secondly the recommendations," said Mr. Kean. "We have got some very serious recommendations to make, and I think they will be something of great value to the American people. Also, they will hopefully make the country safer."

The deadline for the commission to complete the report is July 26, but before it is released, it must be reviewed by the White House to make sure no sensitive security information is made public.

Mr. Kean said he expects the administration will expedite the clearance process. The senior Democrat on the commission, Lee Hamilton agreed. He told NBC the review is required by law.

"Now, we are not going to let them to distort our report," he said. "We understand this has to go through them. And we already have in place a process by which this will be done. We are going to roll these chapters out and give them to the White House."

Mr. Hamilton stressed the White House will not be making a judgment on the report itself. He said it will be looking for a line here or there that could compromise intelligence gathering or create other national security concerns.